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Poggi G, Klaus F, Pryce CR. Pathophysiology in cortico-amygdala circuits and excessive aversion processing: the role of oligodendrocytes and myelination. Brain Commun 2024; 6:fcae140. [PMID: 38712320 PMCID: PMC11073757 DOI: 10.1093/braincomms/fcae140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 12/27/2023] [Accepted: 04/16/2024] [Indexed: 05/08/2024] Open
Abstract
Stress-related psychiatric illnesses, such as major depressive disorder, anxiety and post-traumatic stress disorder, present with alterations in emotional processing, including excessive processing of negative/aversive stimuli and events. The bidirectional human/primate brain circuit comprising anterior cingulate cortex and amygdala is of fundamental importance in processing emotional stimuli, and in rodents the medial prefrontal cortex-amygdala circuit is to some extent analogous in structure and function. Here, we assess the comparative evidence for: (i) Anterior cingulate/medial prefrontal cortex<->amygdala bidirectional neural circuits as major contributors to aversive stimulus processing; (ii) Structural and functional changes in anterior cingulate cortex<->amygdala circuit associated with excessive aversion processing in stress-related neuropsychiatric disorders, and in medial prefrontal cortex<->amygdala circuit in rodent models of chronic stress-induced increased aversion reactivity; and (iii) Altered status of oligodendrocytes and their oligodendrocyte lineage cells and myelination in anterior cingulate/medial prefrontal cortex<->amygdala circuits in stress-related neuropsychiatric disorders and stress models. The comparative evidence from humans and rodents is that their respective anterior cingulate/medial prefrontal cortex<->amygdala circuits are integral to adaptive aversion processing. However, at the sub-regional level, the anterior cingulate/medial prefrontal cortex structure-function analogy is incomplete, and differences as well as similarities need to be taken into account. Structure-function imaging studies demonstrate that these neural circuits are altered in both human stress-related neuropsychiatric disorders and rodent models of stress-induced increased aversion processing. In both cases, the changes include altered white matter integrity, albeit the current evidence indicates that this is decreased in humans and increased in rodent models. At the cellular-molecular level, in both humans and rodents, the current evidence is that stress disorders do present with changes in oligodendrocyte lineage, oligodendrocytes and/or myelin in these neural circuits, but these changes are often discordant between and even within species. Nonetheless, by integrating the current comparative evidence, this review provides a timely insight into this field and should function to inform future studies-human, monkey and rodent-to ascertain whether or not the oligodendrocyte lineage and myelination are causally involved in the pathophysiology of stress-related neuropsychiatric disorders.
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Affiliation(s)
- Giulia Poggi
- Preclinical Laboratory for Translational Research into Affective Disorders, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, CH-8008 Zurich, Switzerland
| | - Federica Klaus
- Department of Psychiatry, University of California San Diego, San Diego, CA 92093, USA
- Desert-Pacific Mental Illness Research Education and Clinical Center, VA San Diego Healthcare System, San Diego, CA 92093, USA
| | - Christopher R Pryce
- Preclinical Laboratory for Translational Research into Affective Disorders, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, CH-8008 Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, 8057 Zurich, Switzerland
- URPP Adaptive Brain Circuits in Development and Learning (AdaBD), University of Zurich, 8057 Zurich, Switzerland
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Palomar-Alonso N, Lee M, Kim M. Exosomes: Membrane-associated proteins, challenges and perspectives. Biochem Biophys Rep 2024; 37:101599. [PMID: 38145105 PMCID: PMC10746368 DOI: 10.1016/j.bbrep.2023.101599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 11/25/2023] [Accepted: 11/28/2023] [Indexed: 12/26/2023] Open
Abstract
Membrane proteins determine the precise function of each membrane and, therefore, the function of each cell type. These proteins essential roles in cell physiology, participating in the maintenance of the cell metabolism, its homeostasis or promoting proper cell growth. Membrane proteins, as has long been described, are located both in the plasma membrane and in complex subcellular structures. However, they can also be released into the extracellular environment associated with extracellular vesicles (EVs). To date, most of the research have been focused on understanding the role of exosomal RNA in several processes. Recently, there has been increasing interest in studying the function of exosome membrane proteins for exosome-based therapy, but not much research has been done yet on the function of exosome membrane proteins. One of the major limitations of studying exosome membrane proteins and their application to translational research of exosome-based therapeutics is the low yield of exosome isolation. Here, we have introduced a new perspective on exosome membrane protein research by reviewing studies showing the important role of exosome membrane proteins in exosome-based therapies. Furthermore, we have proposed a new strategy to boost the yield of exosome isolation: hybridization of liposomes with exosome-derived membrane. Liposomes have already been reported to affect the cell excitation to increase exosome production in tumor cells. Therefore, increasing cellular uptake of these liposomes would enhance exosome release by increasing cellular excitation. This new perspective could be a breakthrough in exosome-based therapeutic research.
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Affiliation(s)
- Nuria Palomar-Alonso
- Department of Neurology, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea
| | - Mijung Lee
- Department of Neurology, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea
| | - Manho Kim
- Department of Neurology, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea
- Neuroscience Dementia Research Institute, Seoul National University College of Medicine, Seoul, South Korea
- Protein Metabolism Medical Research Center, College of Medicine, Seoul National University Hospital, Seoul, South Korea
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Kaffe D, Kaplanis SI, Karagogeos D. The Roles of Caloric Restriction Mimetics in Central Nervous System Demyelination and Remyelination. Curr Issues Mol Biol 2023; 45:9526-9548. [PMID: 38132442 PMCID: PMC10742427 DOI: 10.3390/cimb45120596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 11/16/2023] [Accepted: 11/22/2023] [Indexed: 12/23/2023] Open
Abstract
The dysfunction of myelinating glial cells, the oligodendrocytes, within the central nervous system (CNS) can result in the disruption of myelin, the lipid-rich multi-layered membrane structure that surrounds most vertebrate axons. This leads to axonal degeneration and motor/cognitive impairments. In response to demyelination in the CNS, the formation of new myelin sheaths occurs through the homeostatic process of remyelination, facilitated by the differentiation of newly formed oligodendrocytes. Apart from oligodendrocytes, the two other main glial cell types of the CNS, microglia and astrocytes, play a pivotal role in remyelination. Following a demyelination insult, microglia can phagocytose myelin debris, thus permitting remyelination, while the developing neuroinflammation in the demyelinated region triggers the activation of astrocytes. Modulating the profile of glial cells can enhance the likelihood of successful remyelination. In this context, recent studies have implicated autophagy as a pivotal pathway in glial cells, playing a significant role in both their maturation and the maintenance of myelin. In this Review, we examine the role of substances capable of modulating the autophagic machinery within the myelinating glial cells of the CNS. Such substances, called caloric restriction mimetics, have been shown to decelerate the aging process by mitigating age-related ailments, with their mechanisms of action intricately linked to the induction of autophagic processes.
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Affiliation(s)
- Despoina Kaffe
- Department of Biology, University of Crete, Vassilika Vouton, 70013 Heraklion, Greece;
| | - Stefanos Ioannis Kaplanis
- Department of Basic Science, School of Medicine, University of Crete, Vassilika Vouton, 70013 Heraklion, Greece;
- Institute of Molecular Biology & Biotechnology (IMBB), Foundation for Research and Technology-Hellas (FORTH), Vassilika Vouton, 70013 Heraklion, Greece
| | - Domna Karagogeos
- Department of Basic Science, School of Medicine, University of Crete, Vassilika Vouton, 70013 Heraklion, Greece;
- Institute of Molecular Biology & Biotechnology (IMBB), Foundation for Research and Technology-Hellas (FORTH), Vassilika Vouton, 70013 Heraklion, Greece
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Maliha F, Adnan A. Mechanical Responses of a Single Myelin Layer: A Molecular Simulation Study. Biomolecules 2023; 13:1525. [PMID: 37892207 PMCID: PMC10605433 DOI: 10.3390/biom13101525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 10/06/2023] [Accepted: 10/12/2023] [Indexed: 10/29/2023] Open
Abstract
The myelin sheath provides insulation to the brain's neuron cells, which aids in signal transmission and communication with the body. Degenerated myelin hampers the connection between the glial cells, which are the front row responders during traumatic brain injury mitigation. Thus, the structural integrity of the myelin layer is critical for protecting the brain tissue from traumatic injury. At the molecular level, myelin consists of a lipid bilayer, myelin basic proteins (MBP), proteolipid proteins (PLP), water and ions. Structurally, the myelin sheath is formed by repeatedly wrapping forty or more myelin layers around an axon. Here, we have used molecular dynamic simulations to model and capture the tensile response of a single myelin layer. An openly available molecular dynamic solver, LAMMPS, was used to conduct the simulations. The interatomic potentials for the interacting atoms and molecules were defined using CHARMM force fields. Following a standard equilibration process, the molecular model was stretched uniaxially at a deformation rate of 5 Å/ps. We observed that, at around 10% applied strain, the myelin started to cohesively fail via flaw formation inside the bilayers. Further stretching led to a continued expansion of the defect inside the bilayer, both radially and transversely. This study provides the cellular-level mechanisms of myelin damage due to mechanical load.
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Affiliation(s)
| | - Ashfaq Adnan
- Department of Mechanical and Aerospace Engineering, The University of Texas at Arlington, Arlington, TX 76019, USA;
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Battis K, Xiang W, Winkler J. The Bidirectional Interplay of α-Synuclein with Lipids in the Central Nervous System and Its Implications for the Pathogenesis of Parkinson's Disease. Int J Mol Sci 2023; 24:13270. [PMID: 37686080 PMCID: PMC10487772 DOI: 10.3390/ijms241713270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 08/23/2023] [Accepted: 08/24/2023] [Indexed: 09/10/2023] Open
Abstract
The alteration and aggregation of alpha-synuclein (α-syn) play a crucial role in neurodegenerative diseases collectively termed as synucleinopathies, including Parkinson's disease (PD). The bidirectional interaction of α-syn with lipids and biomembranes impacts not only α-syn aggregation but also lipid homeostasis. Indeed, lipid composition and metabolism are severely perturbed in PD. One explanation for lipid-associated alterations may involve structural changes in α-syn, caused, for example, by missense mutations in the lipid-binding region of α-syn as well as post-translational modifications such as phosphorylation, acetylation, nitration, ubiquitination, truncation, glycosylation, and glycation. Notably, different strategies targeting the α-syn-lipid interaction have been identified and are able to reduce α-syn pathology. These approaches include the modulation of post-translational modifications aiming to reduce the aggregation of α-syn and modify its binding properties to lipid membranes. Furthermore, targeting enzymes involved in various steps of lipid metabolism and exploring the neuroprotective potential of lipids themselves have emerged as novel therapeutic approaches. Taken together, this review focuses on the bidirectional crosstalk of α-syn and lipids and how alterations of this interaction affect PD and thereby open a window for therapeutic interventions.
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Affiliation(s)
| | | | - Jürgen Winkler
- Department of Molecular Neurology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, 91054 Erlangen, Germany; (K.B.); (W.X.)
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Chung HL, Ye Q, Park YJ, Zuo Z, Mok JW, Kanca O, Tattikota SG, Lu S, Perrimon N, Lee HK, Bellen HJ. Very-long-chain fatty acids induce glial-derived sphingosine-1-phosphate synthesis, secretion, and neuroinflammation. Cell Metab 2023; 35:855-874.e5. [PMID: 37084732 PMCID: PMC10160010 DOI: 10.1016/j.cmet.2023.03.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 01/10/2023] [Accepted: 03/29/2023] [Indexed: 04/23/2023]
Abstract
VLCFAs (very-long-chain fatty acids) are the most abundant fatty acids in myelin. Hence, during demyelination or aging, glia are exposed to higher levels of VLCFA than normal. We report that glia convert these VLCFA into sphingosine-1-phosphate (S1P) via a glial-specific S1P pathway. Excess S1P causes neuroinflammation, NF-κB activation, and macrophage infiltration into the CNS. Suppressing the function of S1P in fly glia or neurons, or administration of Fingolimod, an S1P receptor antagonist, strongly attenuates the phenotypes caused by excess VLCFAs. In contrast, elevating the VLCFA levels in glia and immune cells exacerbates these phenotypes. Elevated VLCFA and S1P are also toxic in vertebrates based on a mouse model of multiple sclerosis (MS), experimental autoimmune encephalomyelitis (EAE). Indeed, reducing VLCFA with bezafibrate ameliorates the phenotypes. Moreover, simultaneous use of bezafibrate and fingolimod synergizes to improve EAE, suggesting that lowering VLCFA and S1P is a treatment avenue for MS.
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Affiliation(s)
- Hyung-Lok Chung
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA.
| | - Qi Ye
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Department of Pediatrics, Section of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ye-Jin Park
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Zhongyuan Zuo
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jung-Wan Mok
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Oguz Kanca
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | | | - Shenzhao Lu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Nobert Perrimon
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA; Howard Hughes Medical Institute and Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Hyun Kyoung Lee
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Department of Pediatrics, Section of Neurology, Baylor College of Medicine, Houston, TX 77030, USA.
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA.
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Putka AF, Mato JP, McLoughlin HS. Myelinating Glia: Potential Therapeutic Targets in Polyglutamine Spinocerebellar Ataxias. Cells 2023; 12:cells12040601. [PMID: 36831268 PMCID: PMC9953858 DOI: 10.3390/cells12040601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/09/2023] [Accepted: 02/11/2023] [Indexed: 02/15/2023] Open
Abstract
Human studies, in combination with animal and cellular models, support glial cells as both major contributors to neurodegenerative diseases and promising therapeutic targets. Among glial cells, oligodendrocytes and Schwann cells are the myelinating glial cells of the central and peripheral nervous system, respectively. In this review, we discuss the contributions of these central and peripheral myelinating glia to the pathomechanisms of polyglutamine (polyQ) spinocerebellar ataxia (SCA) types 1, 2, 3, 6, 7, and 17. First, we highlight the function of oligodendrocytes in healthy conditions and how they are disrupted in polyQ SCA patients and diseased model systems. We then cover the role of Schwann cells in peripheral nerve function and repair as well as their possible role in peripheral neuropathy in polyQ SCAs. Finally, we discuss potential polyQ SCA therapeutic interventions in myelinating glial.
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Affiliation(s)
- Alexandra F. Putka
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Juan P. Mato
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Hayley S. McLoughlin
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
- Correspondence:
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Erythrocyte Plasma Membrane Lipid Composition Mirrors That of Neurons and Glial Cells in Murine Experimental In Vitro and In Vivo Inflammation. Cells 2023; 12:cells12040561. [PMID: 36831228 PMCID: PMC9953778 DOI: 10.3390/cells12040561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 01/30/2023] [Accepted: 02/06/2023] [Indexed: 02/12/2023] Open
Abstract
Lipid membrane turnover and myelin repair play a central role in diseases and lesions of the central nervous system (CNS). The aim of the present study was to analyze lipid composition changes due to inflammatory conditions. We measured the fatty acid (FA) composition in erythrocytes (RBCs) and spinal cord tissue (gas chromatography) derived from mice affected by experimental allergic encephalomyelitis (EAE) in acute and remission phases; cholesterol membrane content (Filipin) and GM1 membrane assembly (CT-B) in EAE mouse RBCs, and in cultured neurons, oligodendroglial cells and macrophages exposed to inflammatory challenges. During the EAE acute phase, the RBC membrane showed a reduction in polyunsaturated FAs (PUFAs) and an increase in saturated FAs (SFAs) and the omega-6/omega-3 ratios, followed by a restoration to control levels in the remission phase in parallel with an increase in monounsaturated fatty acid residues. A decrease in PUFAs was also shown in the spinal cord. CT-B staining decreased and Filipin staining increased in RBCs during acute EAE, as well as in cultured macrophages, neurons and oligodendrocyte precursor cells exposed to inflammatory challenges. This regulation in lipid content suggests an increased cell membrane rigidity during the inflammatory phase of EAE and supports the investigation of peripheral cell membrane lipids as possible biomarkers for CNS lipid membrane concentration and assembly.
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Naeem AG, El-Naga RN, Michel HE. Nebivolol elicits a neuroprotective effect in the cuprizone model of multiple sclerosis in mice: emphasis on M1/M2 polarization and inhibition of NLRP3 inflammasome activation. Inflammopharmacology 2022; 30:2197-2209. [PMID: 35948811 DOI: 10.1007/s10787-022-01045-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 07/23/2022] [Indexed: 11/05/2022]
Abstract
BACKGROUND AND AIM Multiple sclerosis (MS) is a demyelinating neurodegenerative inflammatory disease affecting mainly young adults. Microgliosis-derived neuroinflammation represents a key hallmark in MS pathology and progression. Nebivolol (Neb) demonstrated antioxidant, anti-inflammatory and neuroprotective properties in several brain pathologies. This study was conducted to investigate the potential neuroprotective effect of Neb in the cuprizone (Cup) model of MS. METHODS C57Bl/6 mice were fed 0.2% Cup mixed into rodent chow for 5 weeks. Neb (5 and 10 mg/kg/day) was administered by oral gavage during the last 2 weeks. RESULTS Neb prevented Cup-induced weight loss and motor deficits as evidenced by increased latency to fall in the rotarod test and enhanced locomotor activity as compared to Cup-intoxicated mice. Neb reversed Cup-induced demyelination as confirmed by Luxol fast blue staining and myelin basic protein western blotting. Administration of Neb modulated microglial activation status by suppressing M1 markers (Iba-1, CD86, iNOS, NO and TNF-α) and increasing M2 markers (Arg-1 and IL-10) as compared to Cup-fed mice. Furthermore, Neb hindered NLRP3/caspase-1/IL-18 inflammatory cascade and alleviated oxidative stress by reducing lipid peroxidation, as well as increasing catalase and superoxide dismutase activities. CONCLUSION These findings suggest the potential neuroprotective effect of Neb in the Cup-induced model of MS in mice, at least partially by virtue of shifting microglia towards M2 phenotype, mitigation of NLRP3 inflammasome activation and alleviation of oxidative stress.
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Affiliation(s)
- Antoinette G Naeem
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt
| | - Reem N El-Naga
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt
| | - Haidy E Michel
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt.
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Sadler GL, Lewis KN, Narayana VK, De Souza DP, Mason J, McLean C, Gonsalvez DG, Turner BJ, Barton SK. Lipid Metabolism Is Dysregulated in the Motor Cortex White Matter in Amyotrophic Lateral Sclerosis. Metabolites 2022; 12:metabo12060554. [PMID: 35736487 PMCID: PMC9230865 DOI: 10.3390/metabo12060554] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/08/2022] [Accepted: 06/13/2022] [Indexed: 11/16/2022] Open
Abstract
Lipid metabolism is profoundly dysregulated in amyotrophic lateral sclerosis (ALS), yet the lipid composition of the white matter, where the myelinated axons of motor neurons are located, remains uncharacterised. We aimed to comprehensively characterise how myelin is altered in ALS by assessing its lipid and protein composition. We isolated white matter from the motor cortex from post-mortem tissue of ALS patients (n = 8 sporadic ALS cases and n = 6 familial ALS cases) and age- and sex-matched controls (n = 8) and conducted targeted lipidomic analyses, qPCR for gene expression of relevant lipid metabolising enzymes and Western blotting for myelin proteins. We also quantified myelin density by using spectral confocal reflectance microscopy (SCoRe). Whilst myelin protein composition was similar in ALS and control tissue, both the lipid levels and the expression of their corresponding enzymes were dysregulated, highlighting altered lipid metabolism in the white matter as well as a likely change in myelin composition. Altered myelin composition could contribute to motor neuron dysfunction, and this highlights how oligodendrocytes may play a critical role in ALS pathogenesis.
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Affiliation(s)
- Gemma L. Sadler
- Florey Institute of Neuroscience and Mental Health, Melbourne 3052, Australia; (G.L.S.); (K.N.L.); (J.M.); (B.J.T.)
| | - Katherine N. Lewis
- Florey Institute of Neuroscience and Mental Health, Melbourne 3052, Australia; (G.L.S.); (K.N.L.); (J.M.); (B.J.T.)
| | - Vinod K. Narayana
- Metabolomics Australia, Bio21 Institute, University of Melbourne, Melbourne 3052, Australia; (V.K.N.); (D.P.D.S.)
| | - David P. De Souza
- Metabolomics Australia, Bio21 Institute, University of Melbourne, Melbourne 3052, Australia; (V.K.N.); (D.P.D.S.)
| | - Joel Mason
- Florey Institute of Neuroscience and Mental Health, Melbourne 3052, Australia; (G.L.S.); (K.N.L.); (J.M.); (B.J.T.)
| | - Catriona McLean
- Victorian Brain Bank, Florey Institute of Neuroscience and Mental Health, Melbourne 3052, Australia;
| | - David G. Gonsalvez
- Department of Anatomy and Developmental Biology, Monash University, Melbourne 3168, Australia;
| | - Bradley J. Turner
- Florey Institute of Neuroscience and Mental Health, Melbourne 3052, Australia; (G.L.S.); (K.N.L.); (J.M.); (B.J.T.)
| | - Samantha K. Barton
- Florey Institute of Neuroscience and Mental Health, Melbourne 3052, Australia; (G.L.S.); (K.N.L.); (J.M.); (B.J.T.)
- Correspondence:
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Application of the adverse outcome pathway concept for investigating developmental neurotoxicity potential of Chinese herbal medicines by using human neural progenitor cells in vitro. Cell Biol Toxicol 2022; 39:319-343. [PMID: 35701726 PMCID: PMC10042984 DOI: 10.1007/s10565-022-09730-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 05/10/2022] [Indexed: 12/16/2022]
Abstract
Adverse outcome pathways (AOPs) are organized sequences of key events (KEs) that are triggered by a xenobiotic-induced molecular initiating event (MIE) and summit in an adverse outcome (AO) relevant to human or ecological health. The AOP framework causally connects toxicological mechanistic information with apical endpoints for application in regulatory sciences. AOPs are very useful to link endophenotypic, cellular endpoints in vitro to adverse health effects in vivo. In the field of in vitro developmental neurotoxicity (DNT), such cellular endpoints can be assessed using the human "Neurosphere Assay," which depicts different endophenotypes for a broad variety of neurodevelopmental KEs. Combining this model with large-scale transcriptomics, we evaluated DNT hazards of two selected Chinese herbal medicines (CHMs) Lei Gong Teng (LGT) and Tian Ma (TM), and provided further insight into their modes-of-action (MoA). LGT disrupted hNPC migration eliciting an exceptional migration endophenotype. Time-lapse microscopy and intervention studies indicated that LGT disturbs laminin-dependent cell adhesion. TM impaired oligodendrocyte differentiation in human but not rat NPCs and activated a gene expression network related to oxidative stress. The LGT results supported a previously published AOP on radial glia cell adhesion due to interference with integrin-laminin binding, while the results of TM exposure were incorporated into a novel putative, stressor-based AOP. This study demonstrates that the combination of phenotypic and transcriptomic analyses is a powerful tool to elucidate compounds' MoA and incorporate the results into novel or existing AOPs for a better perception of the DNT hazard in a regulatory context.
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Fatty acid dysregulation in the anterior cingulate cortex of depressed suicides with a history of child abuse. Transl Psychiatry 2021; 11:535. [PMID: 34663786 PMCID: PMC8523684 DOI: 10.1038/s41398-021-01657-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 09/23/2021] [Accepted: 10/01/2021] [Indexed: 12/19/2022] Open
Abstract
Child abuse (CA) strongly increases the lifetime risk of suffering from major depression and predicts an unfavorable course for the illness. Severe CA has been associated with a specific dysregulation of oligodendrocyte function and thinner myelin sheaths in the human anterior cingulate cortex (ACC) white matter. Given that myelin is extremely lipid-rich, it is plausible that these findings may be accompanied by a disruption of the lipid profile that composes the myelin sheath. This is important to explore since the composition of fatty acids (FA) in myelin phospholipids can influence its stability, permeability, and compactness. Therefore, the objective of this study was to quantify and compare FA concentrations in postmortem ACC white matter in the choline glycerophospholipid pool (ChoGpl), a key myelin phospholipid pool, between adult depressed suicides with a history of CA (DS-CA) matched depressed suicides without CA (DS) and healthy non-psychiatric controls (CTRL). Total lipids were extracted from 101 subjects according to the Folch method and separated into respective classes using thin-layer chromatography. FA methyl esters from the ChoGpl fraction were quantified using gas chromatography. Our analysis revealed specific effects of CA in FAs from the arachidonic acid synthesis pathway, which was further validated with RNA-sequencing data. Furthermore, the concentration of most FAs was found to decrease with age. By extending the previous molecular level findings linking CA with altered myelination in the ACC, these results provide further insights regarding white matter alterations associated with early-life adversity.
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Garcia Corrales AV, Haidar M, Bogie JFJ, Hendriks JJA. Fatty Acid Synthesis in Glial Cells of the CNS. Int J Mol Sci 2021; 22:ijms22158159. [PMID: 34360931 PMCID: PMC8348209 DOI: 10.3390/ijms22158159] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/22/2021] [Accepted: 07/26/2021] [Indexed: 12/12/2022] Open
Abstract
Fatty acids (FAs) are of crucial importance for brain homeostasis and neural function. Glia cells support the high demand of FAs that the central nervous system (CNS) needs for its proper functioning. Additionally, FAs can modulate inflammation and direct CNS repair, thereby contributing to brain pathologies such Alzheimer’s disease or multiple sclerosis. Intervention strategies targeting FA synthesis in glia represents a potential therapeutic opportunity for several CNS diseases.
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Affiliation(s)
- Aida V Garcia Corrales
- Department of Immunology and Infection, Biomedical Research Institute, Hasselt University, 3590 Diepenbeek, Belgium
| | - Mansour Haidar
- Department of Immunology and Infection, Biomedical Research Institute, Hasselt University, 3590 Diepenbeek, Belgium
| | - Jeroen F J Bogie
- Department of Immunology and Infection, Biomedical Research Institute, Hasselt University, 3590 Diepenbeek, Belgium
| | - Jerome J A Hendriks
- Department of Immunology and Infection, Biomedical Research Institute, Hasselt University, 3590 Diepenbeek, Belgium
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14
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Saeedimasine M, Montanino A, Kleiven S, Villa A. Elucidating Axonal Injuries Through Molecular Modelling of Myelin Sheaths and Nodes of Ranvier. Front Mol Biosci 2021; 8:669897. [PMID: 34250015 PMCID: PMC8260694 DOI: 10.3389/fmolb.2021.669897] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 04/22/2021] [Indexed: 12/19/2022] Open
Abstract
Around half of the traumatic brain injuries are thought to be axonal damage. Disruption of the cellular membranes, or alternatively cytoskeletal damage has been suggested as possible injury trigger. Here, we have used molecular models to have a better insight on the structural and mechanical properties of axon sub-cellular components. We modelled myelin sheath and node of Ranvier as lipid bilayers at a coarse grained level. We built ex-novo a model for the myelin. Lipid composition and lipid saturation were based on the available experimental data. The model contains 17 different types of lipids, distributed asymmetrically between two leaflets. Molecular dynamics simulations were performed to characterize the myelin and node-of-Ranvier bilayers at equilibrium and under deformation and compared to previous axolemma simulations. We found that the myelin bilayer has a slightly higher area compressibility modulus and higher rupture strain than node of Ranvier. Compared to the axolemma in unmyelinated axon, mechanoporation occurs at 50% higher strain in the myelin and at 23% lower strain in the node of Ranvier in myelinated axon. Combining the results with finite element simulations of the axon, we hypothesizes that myelin does not rupture at the thresholds proposed in the literature for axonal injury while rupture may occur at the node of Ranvier. The findings contribute to increases our knowledge of axonal sub-cellular components and help to understand better the mechanism behind axonal brain injury.
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Affiliation(s)
- Marzieh Saeedimasine
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Annaclaudia Montanino
- Division of Neuronic Engineering, KTH-Royal Institute of Technology, Stockholm, Sweden
| | - Svein Kleiven
- Division of Neuronic Engineering, KTH-Royal Institute of Technology, Stockholm, Sweden
| | - Alessandra Villa
- PDC-Center for High Performance Computing, KTH-Royal Institute of Technology, Stockholm, Sweden
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15
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Piredda GF, Hilbert T, Thiran JP, Kober T. Probing myelin content of the human brain with MRI: A review. Magn Reson Med 2020; 85:627-652. [PMID: 32936494 DOI: 10.1002/mrm.28509] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 08/12/2020] [Accepted: 08/17/2020] [Indexed: 12/11/2022]
Abstract
Rapid and efficient transmission of electric signals among neurons of vertebrates is ensured by myelin-insulating sheaths surrounding axons. Human cognition, sensation, and motor functions rely on the integrity of these layers, and demyelinating diseases often entail serious cognitive and physical impairments. Magnetic resonance imaging radically transformed the way these disorders are monitored, offering an irreplaceable tool to noninvasively examine the brain structure. Several advanced techniques based on MRI have been developed to provide myelin-specific contrasts and a quantitative estimation of myelin density in vivo. Here, the vast offer of acquisition strategies developed to date for this task is reviewed. Advantages and pitfalls of the different approaches are compared and discussed.
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Affiliation(s)
- Gian Franco Piredda
- Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland.,Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.,LTS5, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Tom Hilbert
- Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland.,Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.,LTS5, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Jean-Philippe Thiran
- Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.,LTS5, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Tobias Kober
- Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland.,Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.,LTS5, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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16
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Poitelon Y, Kopec AM, Belin S. Myelin Fat Facts: An Overview of Lipids and Fatty Acid Metabolism. Cells 2020; 9:cells9040812. [PMID: 32230947 PMCID: PMC7226731 DOI: 10.3390/cells9040812] [Citation(s) in RCA: 141] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 03/24/2020] [Accepted: 03/25/2020] [Indexed: 12/11/2022] Open
Abstract
Myelin is critical for the proper function of the nervous system and one of the most complex cell–cell interactions of the body. Myelination allows for the rapid conduction of action potentials along axonal fibers and provides physical and trophic support to neurons. Myelin contains a high content of lipids, and the formation of the myelin sheath requires high levels of fatty acid and lipid synthesis, together with uptake of extracellular fatty acids. Recent studies have further advanced our understanding of the metabolism and functions of myelin fatty acids and lipids. In this review, we present an overview of the basic biology of myelin lipids and recent insights on the regulation of fatty acid metabolism and functions in myelinating cells. In addition, this review may serve to provide a foundation for future research characterizing the role of fatty acids and lipids in myelin biology and metabolic disorders affecting the central and peripheral nervous system.
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17
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Saeedimasine M, Montanino A, Kleiven S, Villa A. Role of lipid composition on the structural and mechanical features of axonal membranes: a molecular simulation study. Sci Rep 2019; 9:8000. [PMID: 31142762 PMCID: PMC6541598 DOI: 10.1038/s41598-019-44318-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 05/13/2019] [Indexed: 12/16/2022] Open
Abstract
The integrity of cellular membranes is critical for the functionality of axons. Failure of the axonal membranes (plasma membrane and/or myelin sheath) can be the origin of neurological diseases. The two membranes differ in the content of sphingomyelin and galactosylceramide lipids. We investigate the relation between lipid content and bilayer structural-mechanical properties, to better understand the dependency of membrane properties on lipid composition. A sphingomyelin/phospholipid/cholesterol bilayer is used to mimic a plasma membrane and a galactosylceramide/phospholipid/cholesterol bilayer to mimic a myelin sheath. Molecular dynamics simulations are performed at atomistic and coarse-grained levels to characterize the bilayers at equilibrium and under deformation. For comparison, simulations of phospholipid and phospholipid/cholesterol bilayers are also performed. The results clearly show that the bilayer biomechanical and structural features depend on the lipid composition, independent of the molecular models. Both galactosylceramide or sphingomyelin lipids increase the order of aliphatic tails and resistance to water penetration. Having 30% galactosylceramide increases the bilayers stiffness. Galactosylceramide lipids pack together via sugar-sugar interactions and hydrogen-bond phosphocholine with a correlated increase of bilayer thickness. Our findings provide a molecular insight on role of lipid content in natural membranes.
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Affiliation(s)
- Marzieh Saeedimasine
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Annaclaudia Montanino
- Division of Neuronic Engineering, KTH-Royal Institute of Technology, Huddinge, Sweden
| | - Svein Kleiven
- Division of Neuronic Engineering, KTH-Royal Institute of Technology, Huddinge, Sweden
| | - Alessandra Villa
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden.
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18
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Pathological transitions in myelin membranes driven by environmental and multiple sclerosis conditions. Proc Natl Acad Sci U S A 2018; 115:11156-11161. [PMID: 30322944 PMCID: PMC6217380 DOI: 10.1073/pnas.1804275115] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
In demyelination diseases, such as multiple sclerosis, the structure of the axons’ protective sheaths is disrupted. Due to the proximity of cytoplasmic myelin membrane to structural phase transition, minor alterations in the local environmental conditions can have devastating results. Using small-angle X-ray scattering and cryogenic transmission electron microscopy, we show that drastic structural reorganization and instabilities of myelin membrane are linked to specific environmental conditions and molecular composition in healthy and diseased states. These instabilities involve phase transition from the healthy lamellar membranes to pathological inverted hexagonal phase. These results highlight that local environmental conditions are critical for myelin function and should be considered as alternative routes for early pathology and as a means to avoid the initiation of demyelination. Multiple sclerosis (MS) is an autoimmune disease, leading to the destruction of the myelin sheaths, the protective layers surrounding the axons. The etiology of the disease is unknown, although there are several postulated environmental factors that may contribute to it. Recently, myelin damage was correlated to structural phase transition from a healthy stack of lamellas to a diseased inverted hexagonal phase as a result of the altered lipid stoichiometry and low myelin basic protein (MBP) content. In this work, we show that environmental conditions, such as buffer salinity and temperature, induce the same pathological phase transition as in the case of the lipid composition in the absence of MBP. These phase transitions have different transition points, which depend on the lipid’s compositions, and are ion specific. In extreme environmental conditions, we find an additional dense lamellar phase and that the native lipid composition results in similar pathology as the diseased composition. These findings demonstrate that several local environmental changes can trigger pathological structural changes. We postulate that these structural modifications result in myelin membrane vulnerability to the immune system attacks and thus can help explain MS etiology.
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19
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Critical and off-critical miscibility transitions in model extracellular and cytoplasmic myelin lipid monolayers. Biophys J 2011; 100:1490-8. [PMID: 21402031 DOI: 10.1016/j.bpj.2011.02.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Revised: 01/15/2011] [Accepted: 02/03/2011] [Indexed: 11/22/2022] Open
Abstract
Monolayers based on the composition of the cytoplasmic (CYT) or extracellular (EXT) sides of the myelin bilayer form coexisting immiscible liquid phases similar to the liquid-ordered/liquid-disordered phases in phospholipid/cholesterol monolayers. Increasing the temperature or surface pressure causes the two liquid phases to mix, although in significantly different fashion for the CYT and EXT monolayers. The cerebroside-rich EXT monolayer is near a critical composition and the domains undergo coalescence and a circle-to-stripe transition along with significant roughening of the domain boundaries before mixing. The phase transition in the cerebroside-free cytoplasmic side occurs abruptly without domain coalescence; hence, the cytoplasmic monolayer is not near a critical composition, although the domains exhibit shape instabilities within 1-2 mN/m of the transition. The change in mixing pressure decreases significantly with temperature for the EXT monolayer, with dΠ(crit)/dT ∼ 1.5 mN/m/°C, but the mixing pressure of the CYT monolayer varies little with temperature. This is due to the differences in the nonideality of cholesterol interactions with cerebrosides (EXT) relative to phospholipids (CYT). EXT monolayers based on the composition of white matter from marmosets with experimental allergic encephalomyelitis (EAE), an animal model of multiple sclerosis, remain phase-separated at higher surface pressures than control, while EAE CYT monolayers are similar to control. Myelin basic protein, when added to the CYT monolayer, increases lipid miscibility in CYT monolayers; likely done by altering the dipole density difference between the two phases.
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20
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Relating domain size distribution to line tension and molecular dipole density in model cytoplasmic myelin lipid monolayers. Proc Natl Acad Sci U S A 2011; 108:9425-30. [PMID: 21606329 DOI: 10.1073/pnas.1106368108] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
We fit the size distribution of liquid-ordered (L(o)) domains measured from fluorescence images of model cytoplasmic myelin monolayers with an equilibrium thermodynamic expression that includes the competing effects of line tension, λ, dipole density difference, Δm, and the mixing entropy. From these fits, we extract the line tension, λ, and dipole density difference, Δm, between the L(o) and liquid-disordered (L(d)) phases. Both λ and Δm decrease with increasing surface pressure, , although λ/Δm(2) remains roughly constant as the monolayer approaches the miscibility surface pressure. As a result, the mean domain size changed little with surface pressure, although the polydispersity increased significantly. The most probable domain radius was significantly smaller than that predicted by the energy alone, showing that the mixing entropy promotes a greater number of smaller domains. Our results also explain why domain shapes are stable; at equilibrium, only a small fraction of the domains are large enough to undergo theoretically predicted shape fluctuations. Monolayers based on the composition of myelin from animals with experimental allergic encephalomyelitis had slightly lower values of λ and Δm, and a higher area fraction of domains, than control monolayers at all . While it is premature to generalize these results to myelin bilayers, our results show that the domain distribution in myelin may be an equilibrium effect and that subtle changes in surface pressure and composition can alter the distribution of material in the monolayer, which will likely also alter the interactions between monolayers important to the adhesion of the myelin sheath.
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21
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Interaction forces and adhesion of supported myelin lipid bilayers modulated by myelin basic protein. Proc Natl Acad Sci U S A 2009; 106:3154-9. [PMID: 19218452 DOI: 10.1073/pnas.0813110106] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Force-distance measurements between supported lipid bilayers mimicking the cytoplasmic surface of myelin at various surface coverages of myelin basic protein (MBP) indicate that maximum adhesion and minimum cytoplasmic spacing occur when each negative lipid in the membrane can bind to a positive arginine or lysine group on MBP. At the optimal lipid/protein ratio, additional attractive forces are provided by hydrophobic, van der Waals, and weak dipolar interactions between zwitterionic groups on the lipids and MBP. When MBP is depleted, the adhesion decreases and the cytoplasmic space swells; when MBP is in excess, the bilayers swell even more. Excess MBP forms a weak gel between the surfaces, which collapses on compression. The organization and proper functioning of myelin can be understood in terms of physical noncovalent forces that are optimized at a particular combination of both the amounts of and ratio between the charged lipids and MBP. Thus loss of adhesion, possibly contributing to demyelination, can be brought about by either an excess or deficit of MBP or anionic lipids.
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22
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A double mutation of MBP(83-99) peptide induces IL-4 responses and antagonizes IFN-gamma responses. J Neuroimmunol 2008; 200:77-89. [PMID: 18675465 DOI: 10.1016/j.jneuroim.2008.06.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2008] [Revised: 06/05/2008] [Accepted: 06/09/2008] [Indexed: 11/20/2022]
Abstract
A number of treatment options are available to multiple sclerosis patients, however this needs to be improved. Herein, we designed and synthesized a number of peptides by mutating principal TCR contact residues based on MBP(83-99) peptide epitope. Immunization of SJL/J mice with MBP(83-99) and mutant [A(91)]MBP(83-99), [E(91)]MBP(83-99), [F(91)]MBP(83-99), [Y(91)]MBP(83-99), and [R(91), A(96)]MBP(83-99) peptides, induced IFN-gamma, and only [R(91), A(96)]MBP(83-99) mutant peptide was able to induce IL-4 secretion by T cells. T cells against the native MBP(83-99) peptide cross-reacted with all peptides except [Y(91)]MBP(83-99) and [R(91),A(96)]MBP(83-99). The double mutant [R(91), A(96)]MBP(83-99) was able to antagonize IFN-gamma production in vitro by T cells against the native MBP(83-99) peptide. Antibodies generated to [R(91), A(96)]MBP(83-99) did not cross-react with whole MBP protein. Molecular modeling between peptide analogs and H2 I-A(s) demonstrated novel interactions. The [R(91), A(96)]MBP(83-99) double mutant peptide analog is the most promising for further therapeutic studies.
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23
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Lund BT, Chakryan Y, Ashikian N, Mnatsakanyan L, Bevan CJ, Aguilera R, Gallaher T, Jakowec MW. Association of MBP peptides with Hsp70 in normal appearing human white matter. J Neurol Sci 2006; 249:122-34. [PMID: 16842822 DOI: 10.1016/j.jns.2006.05.066] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2005] [Revised: 05/04/2006] [Accepted: 05/26/2006] [Indexed: 10/24/2022]
Abstract
Multiple Sclerosis is an autoimmune disease directed against myelin proteins. The etiology of MS is poorly defined though, with no definitive causative agent yet identified. It has been hypothesized that MS may be a multifactorial disease resulting in the same end product: the destruction of myelin by the immune system. In this report we describe a potential role for heat shock proteins in the pathogenesis of MS. We isolated Hsp70 from the normal appearing white matter of both MS and normal human brain and found this was actively associated with, among other things, immunodominant MBP peptides. Hsp70-MBP peptide complexes prepared in vitro were shown to be highly immunogenic, with adjuvant-like effects stimulating MBP peptide-specific T cell lines to respond to normally sub-optimal concentrations of peptide. This demonstration of a specific interaction between Hsp70 and different MBP peptides, coupled with the adjuvanticity of this association is suggestive of a possible role for Hsp70 in the immunopathology associated with MS.
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Affiliation(s)
- Brett T Lund
- Department of Neurology, Keck School of Medicine, University of Southern California, McKibben Annex, Room 246, 1333 San Pablo Street, Los Angeles, California 90033, United States.
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24
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Ohler B, Graf K, Bragg R, Lemons T, Coe R, Genain C, Israelachvili J, Husted C. Role of lipid interactions in autoimmune demyelination. Biochim Biophys Acta Mol Basis Dis 2004; 1688:10-7. [PMID: 14732476 DOI: 10.1016/j.bbadis.2003.10.001] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A morphological transformation involving loss of adhesion between myelin lamellae and formation of myelin vesicles has been described as a mechanism for demyelination in multiple sclerosis and marmoset experimental allergic encephalomyelitis (EAE). Although protein interactions are involved in maintaining normal myelin structure, we describe here how lipids contribute to myelin stability and how lipid changes in EAE, including increases in lipid polyunsaturation and negatively charged phosphatidylserine (PS), promote demyelination. Three physico-chemical techniques were used to identify these changes: (1) Langmuir monolayer isotherms indicated that EAE white matter lipids were significantly more "expanded" (fluid) than controls. (2) NMR spectroscopy indicated that EAE myelin lipids were more polyunsaturated than controls. (3) High-performance liquid chromatography (HPLC) with an evaporative light scattering detector indicated increased PS in EAE compared to controls, while sphingomyelin (SM), sulfatides and phosphatidylcholine (PC) were decreased. We present a physical model considering electrostatic, van der Waals and undulation forces to quantify the effect of these changes on myelin adhesion at the extracellular interface. Taken together, the isotherm, NMR, HPLC and modeling results support a mechanism for autoimmune demyelination whereby the composition of myelin lipids is altered in a manner that increases myelin fluidity, decreases myelin adhesion, increases membrane curvature, and promotes vesiculation.
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Affiliation(s)
- Benjamin Ohler
- Center for the Study of Neurodegenerative Disorders, Neuroscience Research Institute, Biological Sciences 2, University of California, Santa Barbara, CA 93106-5060, USA
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25
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Abstract
Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS). Significant progress has been made in our understanding of the etiology of MS. MS is widely believed to be an autoimmune disease that results from aberrant immune responses to CNS antigens. T cells are considered to be crucial in orchestrating an immunopathological cascade that results in damage to the myelin sheath. This review summarizes the currently available data supporting the idea that myelin reactive T cells are actively involved in the immunopathogenesis of MS. Some of the therapeutic strategies for MS are discussed with a focus on immunotherapies that aim to specifically target the myelin reactive T cells.
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Affiliation(s)
- Niels Hellings
- Biomedical Research Institute, Limburg University Center, School for Life Sciences, Transnational University Diepenbeek, Belgium
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26
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Kalbus M, Fleckenstein BT, Offenhäusser M, Blüggel M, Melms A, Meyer HE, Rammensee HG, Martin R, Jung G, Sommer N. Ligand motif of the autoimmune disease-associated mouse MHC class II molecule H2-A(s). Eur J Immunol 2001; 31:551-62. [PMID: 11180120 DOI: 10.1002/1521-4141(200102)31:2<551::aid-immu551>3.0.co;2-p] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The MHC class II molecule H2-A(s), expressed in the SJL mouse strain, is the principle restriction element of autoreactive CD4(+) T cells mediating experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis. We deduced the H2-A(s) ligand motif from the analysis of naturally processed self peptides and from peptide binding studies. Major anchor residues were identified using various sets of substituted and truncated peptides, derived from natural peptide ligands and known H2-A(s) binders like myelin basic protein 81 - 99. The nine-residue H2-A(s) core binding motif comprises an arrangement of anchors in relative positions P1, P4, P6, P7, and P9. The P1 pocket is relatively unspecific and the P6 pocket favors hydrophobic-aliphatic side chains. The P1 pocket contributes little to peptide binding. Primary anchors were identified in P4, P7, and in particular in P9. The preferred anchor residues are Lys (P4), His/Arg (P7), and Pro (P9), respectively. Ala-polysubstituted peptides containing only one of these dominant anchor residues still retain the capacity to bind to H2-A(s). Thus, the presence of only one suitable anchor side chain in P4, P7, or P9 is sufficient for high-affinity peptide binding, at least in the absence of negatively charged side chains nearby. The identified ligand motif facilitates the analysis of immunogenic peptides interacting with H2-A(s) and will allow a better prediction of pathogenetically relevant peptide antigens in the autoimmune mouse model.
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Affiliation(s)
- M Kalbus
- Department of Neurology, Tübingen University, Tübingen, Germany.
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27
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Van Noort JM, van Sechel AC, van Stipdonk MJ, Bajramovic JJ. The small heat shock protein alpha B-crystallin as key autoantigen in multiple sclerosis. PROGRESS IN BRAIN RESEARCH 1999; 117:435-52. [PMID: 9932424 DOI: 10.1016/s0079-6123(08)64031-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- J M Van Noort
- Division of Immunological and Infectious Diseases, TNO Prevention and Health, Leiden, The Netherlands.
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28
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Cohen G, Yakushin S, Dembiec-Cohen D. Protein L-dopa as an index of hydroxyl radical attack on protein tyrosine. Anal Biochem 1998; 263:232-9. [PMID: 9799536 DOI: 10.1006/abio.1998.2766] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
It is widely believed that hydroxyl radicals generated in vivo contribute to damage to macromolecules, such as proteins and DNA. We evaluated methodology based on the transformation of protein tyrosine to L-Dopa, via aromatic ring hydroxylation, as an index of hydroxyl radical attack on proteins. The catechol structure of Dopa makes it amenable to isolation with alumina, followed by HPLC analysis, typically used for the measurement of catecholamines. Because a level of controversy exists about the formation of Dopa by hydroxyl radicals, we conducted a systematic study of the formation of Dopa from tyrosine, tyrosine dipeptides, pure proteins (chymotrypsin and myelin basic protein), and endogenous proteins in tissue homogenates (rat brain), exposed to hydroxylating conditions (Fe2+/EDTA/ascorbate at neutral pH). Dopa residues in peptides and proteins were liberated by acid hydrolysis with 6 M HCl at 145 degrees C for 1 h. A marked lability of Dopa in 6 M HCl under hydrolysis conditions was prevented with added phenol; chymotrypsin and precipitated pellets of brain protein were also protective. Overall recoveries (hydrolysis plus purification procedures) averaged 83.4 +/- 1.7%. This improved analytic procedure may be useful for studying protein damage by hydroxyl radicals.
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Affiliation(s)
- G Cohen
- Department of Neurology and Neurobiology Research Center, Mount Sinai School of Medicine of the City University of New York, New York, New York 10029, USA
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29
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Yehuda S, Rabinovitz S, Mostofsky DI, Huberman M, Sredni B. Essential fatty acid preparation improves biochemical and cognitive functions in experimental allergic encephalomyelitis rats. Eur J Pharmacol 1997; 328:23-9. [PMID: 9203563 DOI: 10.1016/s0014-2999(97)83022-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
This study examined the possible effects of a novel mixture of fatty acids, SR-3 (a specific ratio of alpha-linolenic acids), on brain biochemistry and on learning deficits induced by injection of an agent that induces experimental allergic encephalomyelitis. Treatment with SR-3 caused a decrease in myelin and changes in the fatty acid profile of brain synaptosomes, and a learning deficit. Eighteen days of treatment with SR-3 reversed the biochemical and learning deficit significantly, but did not restore them to normal levels. We propose that, most probably, the main action of SR-3 is the modulation of the cholesterol level, which in turn causes the modulation of the fatty acid profile and enhances learning by allowing improved neuronal communication.
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Affiliation(s)
- S Yehuda
- Department of Psychology, Bar Ilan University, Ramat Gan, Israel
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30
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Hang LM, Nakamura RM. Current concepts and advances in clinical laboratory testing for autoimmune diseases. Crit Rev Clin Lab Sci 1997; 34:275-311. [PMID: 9226106 DOI: 10.3109/10408369708998095] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
This review discusses the current concepts of immunological tolerance, physiological vs. pathological autoimmunity, autoimmune diseases, and laboratory tests helpful in diagnosis. The autoantibodies in organ-specific autoimmune diseases are directed against antigens of the injured organs, whereas the antinuclear antibodies (ANA) detected in systemic autoimmune diseases are detected against a vast array of nuclear and intracellular antigens and peptides necessary for DNA/RNA synthesis, repair, splicing, and transcription. Knowledge of the mean titer and presence or absence of specific ANA types will help predict the nature of the disease and the response to therapy. Noteworthy features of these "ANA profiles" are (1) patients with systemic lupus erythematosus frequently have multiple types of ANA but anti-dsDNA and anti-SM are diagnostic, (2) patients with drug-induced lupus have ANA restricted to antihistone, (3) patients with mixed connective tissue disease have ANA restricted to anti-RNP, (4) patients with CREST (calcinosis, Raynaud's, esophageal dysmotility, sclerodactyly, and telangiectasia) syndrome have ANA restricted to anticentromere, (5) ANA with anti-SS-A/Ro specificity is associated with vasculitis and nephritis, (6) ANA with anti-SS-B/La and anti-nRNP specificities is associated with milder clinical disease, (7) ANAs with anti-Jo-1 and PM-Scl specificities are associated with pulmonary fibrosis and poor prognosis. Technological advances in the fields of molecular immunogenetics are guiding the studies of autoimmune diseases from serological and histopathological evaluations toward search for subcellular risk factors such as chemical and biological agents and susceptibility genes. Knowledge of these factors will help (1) to identify disease susceptibility genes prior to clinical onset and irreversible tissue damage, (2) to avoid environmental risk factors, and (3) to devise specific immunosuppressive strategies.
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Affiliation(s)
- L M Hang
- Department of Pathology, Scripps Clinic and Research Foundation, La Jolla, California 92037, USA
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Vergelli M, Pinet V, Vogt AB, Kalbus M, Malnati M, Riccio P, Long EO, Martin R. HLA-DR-restricted presentation of purified myelin basic protein is independent of intracellular processing. Eur J Immunol 1997; 27:941-51. [PMID: 9130648 DOI: 10.1002/eji.1830270421] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Antigen presentation to CD4+ T cells involves intracellular antigen processing and loading of peptides onto newly synthesized major histocompatibility complex (MHC)-class II molecules. Some antigens, such as the lipid-bound, native form of myelin basic protein (LB-MBP) can also be presented by recycling of cell surface MHC class II molecules. The data reported here demonstrate that a preparation of highly purified, delipidated MBP (HP-MBP) follows yet another presentation pathway. Similar to LB-MBP, presentation of HP-MBP to HLA-DR1-restricted T cells was independent of HLA-DM, of newly synthesized proteins, and of invariant chain expression. However, in contrast to LB-MBP, presentation of HP-MBP was also independent of internalization of surface HLA-DR molecules. The different requirements for the presentation of the two molecular forms of MBP were further confirmed by use of the protease inhibitor E64: presentation of LB-MBP but not of HP-MBP was inhibited after treatment of target cells with E64. Furthermore, intact HP-MPB bound to isolated HLA-DR molecules in vitro with an association rate that was considerably faster than that of short peptides. These results show that presentation of HP-MBP is independent of intracellular processing and suggest that it may be presented to T cells by direct binding to surface HLA-DR molecules.
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Affiliation(s)
- M Vergelli
- Neuroimmunology Branch, NINDS, NIH, Bethesda, MD 20892-1400, USA
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Martin R, McFarland HF. Immunological aspects of experimental allergic encephalomyelitis and multiple sclerosis. Crit Rev Clin Lab Sci 1995; 32:121-82. [PMID: 7598789 DOI: 10.3109/10408369509084683] [Citation(s) in RCA: 310] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Multiple sclerosis (MS) is the most frequent, demyelinating disease of the central nervous system (CNS) in Northern Europeans and North Americans. Despite intensive research its etiology is still unknown, but a T cell-mediated autoimmune pathogenesis is likely to be responsible for the demyelination. This hypothesis is based both on findings in MS patients and studies of an experimental animal model for demyelinating diseases, experimental allergic encephalomyelitis (EAE). Experiments in EAE have not only demonstrated which myelin antigens are able to induce the demyelinating process but also have determined the characteristics of encephalitogenic T cells, that is, their fine specificity, major histocompatibility complex (MHC) restriction, lymphokine secretion, activation requirements, and T cell receptor (TCR) usage. Based on these findings, highly specific and efficient immune interventions have been designed in EAE and have raised hopes that similar approaches could modulate the disease process in MS. Although the examination of the myelin-specific T cell response in MS patients has shown parallels to EAE, this remains an area of intensive research because a number of questions remain. This review summarizes the important lessons from EAE, examines recent findings in MS, and discusses current concepts about how the disease process develops and which steps might be taken to modulate it.
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Affiliation(s)
- R Martin
- Neuroimmunology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892, USA
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